1. Field of the Invention
This invention relates to a combining syringe in which an administrator applies a pressure great enough to force a fluid from a secondary cylinder into a primary cylinder where the fluid is combined and then dispensed through an attaching end. The present invention relates particularly to a combining syringe configured to receive a plurality of cylinders through a slidable plunger of a primary cylinder.
2. Background Art
A multiple fluid combining syringe is used in the preparation of multiple sterile products which are combined into a cylinder prior to being dispensed into the injection site. Formerly, syringes dispensing multiple fluids are seen to incorporate excess parts including a valve assembly having a valved stopper and a valve actuator as described in U.S. Pat. No. 6,997,910.
Thus, there is a need for a multiple fluid combining syringe with an improved configuration, eliminating the need for additional parts, valve assemblies, and eliminating the associated costs for manufacturing and assembling these parts.
Prior art syringe devices are seen to incorporate a sliding piston having a valve as described in U.S. Pat. No. 7,635,344. Before the fluids are combined, a user slides the piston from a first position to a second position in the chamber. When the valve is opened by a user, the fluid is guided into a chamber. This requires a user to perform the additional step of opening the valve which is time consuming. In addition, the valve may fail, rendering the syringe inoperable.
Therefore, there is a need for an improved combining syringe that eliminates the need of having a valve system which reduces the possibility of the system failing.
Maaskamp et al. teach in U.S. Patent Application No. 20080275403 a dual syringe assembly comprising a housing having a pair of proximal ports and a distal port, a primary one way valve within the primary proximal chamber, and a secondary one way valve within the secondary proximal chamber. A user sequentially dispenses a fluid comprising the steps of attaching a connector valve assembly to a primary syringe and a secondary syringe, the connector valve assembly having a primary and secondary one way valve, and a user initially depressing the primary syringe to release the fluid through the primary one way valve and then depressing the secondary syringe. This configuration does not allow a user to combine the fluids.
Hence, there is a need for a syringe having a configuration to accommodate a plurality of separated fluids to be dispensed through a single plunger. The improved method will eliminate the need for additional parts such as a valve stopper and a valve actuator and will allow for combining of fluids prior to dispensing.